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AbstractAbstract
[en] Recent results from ASDEX Upgrade are presented. An improved understanding of energy and particle transport emerges in terms of a 'critical gradient' model for the temperature gradients. Coupling this to particle diffusion explains most of the observed behaviour of the density profiles, in particular the finding that strong central heating reduces the tendency for density profile peaking. Internal transport barriers with Te and Ti in excess of 20 keV (but not simultaneously) have been achieved. By shaping the plasma, a regime with small type II ELMs has been established. Here, the maximum power deposited on the target plates was greatly reduced at constant average power. Also, an increase of the ELM frequency by injection of shallow pellets was demonstrated. ELM free operation is possible in the QH-mode regime previously found in DIII-D which has also been established on ASDEX Upgrade. Regarding stability, a regime with benign NTMs was found. During ECCD stabilisation of NTMs, βN could be increased well above the usual onset level without a reappearance of the NTM. ECRH and ECCD have also been used to control the sawtooth repetition frequency at a moderate fraction of the total heating power. The inner wall of the ASDEX Upgrade vessel has increasingly been covered with tungsten without detrimental effects on plasma performance. Regarding scenario integration, a scenario with a large fraction of non inductively driven current (≥ 50%), but without internal transport barrier has been established. It combines improved confinement (τE=τITER98 ∼ 1:2) and stability (βN ≤ 3:5) at high Greenwald fraction (ne=nGW ∼ 0:85) in steady state and with type II ELMy edge. (author)
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International Atomic Energy Agency, Vienna (Austria); Commissariat a l'Energie Atomique (France); 516 p; ISSN 1562-4153;
; Sep 2003; [13 p.]; 19. IAEA fusion energy conference; Lyon (France); 14-19 Oct 2002; OV/2--1; ISSN 1562-4153;
; Also available on-line: http://www-pub.iaea.org/MTCD/publications/PDF/csp_019c/START.HTM; and on 1 CD-ROM from IAEA, Sales and Promotion Unit: E-mail: sales.publications@iaea.org; Web site: http://www-pub.iaea.org/MTCD/publications/publications.asp; 43 refs, 11 figs


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Report
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Conference
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CHARGED-PARTICLE TRANSPORT THEORY, CLOSED PLASMA DEVICES, CONFINEMENT, CURRENTS, ELEMENTS, HEATING, HIGH-FREQUENCY HEATING, INSTABILITY, MAGNETIC CONFINEMENT, METALS, NON-INDUCTIVE CURRENT DRIVE, PLASMA CONFINEMENT, PLASMA HEATING, PLASMA INSTABILITY, PLASMA MACROINSTABILITIES, REFRACTORY METALS, THERMONUCLEAR DEVICES, TOKAMAK DEVICES, TRANSITION ELEMENTS, TRANSPORT THEORY
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